College of Agriculture and Environmental Sciences

Optimization of Production and Postharvest Practices for Enhanced Yield, Quality and Shelf-Life of Onion (Allium Cepa L.) in Northwest Ethiopia

2026-10-08T11:36:43Z

Optimization of Production and Postharvest Practices for Enhanced Yield, Quality and Shelf-Life of Onion (Allium Cepa L.) in Northwest Ethiopia Yeshiwas, Yebirzaf Onion is an economically important cash crop in Ethiopia and the Amhara Region, which is widely produced under irrigation condition to meet year-round market demand. Despite its importance, however, onion production faces challenges such as low productivity due to a lack of improved varieties with extended shelf life, improper fertilization practices, suboptimal plant density. Studies were conducted in 2021–2023 in North Mecha (Koga), Bahir Dar Zuria (Woramit), and Fogera (Woreta) districts to assess farmers' knowledge and management practices, identify key supply chain constraints, and optimize nitrogen fertilizer rates and plant populations to enhance onion growth, yield, and quality. The study combined a field experiment and a survey. Field experiments were laid out in a factorial arrangement using a Randomized Complete Block Design (RCBD) with three replications. The survey result showed that onion production is dominated by adults households, but faces challenges of input shortages, high costs, and postharvest losses. Seven alternative marketing channels were identified, involving key actors such as farmers, local collectors, brokers, transporters, wholesalers, retailers, and consumers. The majority of the produce (66.15%) was sold to wholesalers. However, producers received only a small share of the final consumer price, while experiencing the highest average postharvest losses among all actors in the supply chain. Similarly, the experimental study indicate that onion growth and yield are significantly influenced by planting density, variety, and nitrogen fertilizer rate across growing location. Hybrid varieties (Russet and Jambar) consistently exhibited superior performance, achieving the highest bulb diameter, weight, harvest index, firmness, total yield, and marketable yield under the planting density of 666,666 plants ha 22 -1 across all locations. Russet and Jambar recorded the highest marketable yields of 28.54 t ha -1 and 26.61 t ha , respectively. Planting at higher densities (666,666 plants ha -1 ) with a spacing of 40cm x 20cm x 5cm between double rows, rows, and plants respectively resulted in the highest marketable yield (28.42 t ha -1 ). Moreover, the application of 82 kg ha -1 nitrogen fertilizer further enhanced growth and yield parameters, with Russet and Jambar achieving yields of 26.50 t ha -1 and 24.57 t ha -1 , respectively, across locations. The hybrid varieties (Russet and Jambar) and optimal nitrogen application rate (82 kg ha -1 ) also provided the highest net benefits. Postharvest quality was significantly influenced by packaging materials, nitrogen fertilizer, and variety. Proper handling allowed onions to be stored for up to one month without significant losses, regardless of the packaging materials used. Russet and Jambar varieties, when produced with optimum nitrogen fertilizer rate and stored on locally constructed shelves exhibited delayed sprouting, minimal decay, lower weight loss, and better firmness. In contrast, Bombay Red and Red Coach varieties showed higher storage losses. The study recommends for producers and traders in the study area, as well as similar to agro-ecologies adopt Russet and Jambar varieties, combined with higher planting densities and 82 kg ha -1 nitrogen fertilizer for improved onion. Storing bulbs on shelves until market conditions improved can contribute to a sustainable onion supply chain. Furthermore, the study found that pre-harvest treatments, such as toppling at 90% neck fall, improved postharvest storage. Onions of Jambar and Russet varieties were able to be stored for up to four weeks without significant loss. The study underscores the need for further exploration, particularly to evaluate various hybrid onion varieties at high plant density levels. The investigation of phosphorus fertilizer is also recommended for -1 future research, and since the study's limitation to a single season and location, further research is needed to test and to validate these findings across multiple locations and repeated years.

Seasonal Population Dynamics of White Mango Scale (Aulacaspis tubercularis (Hemiptera: Diaspididae) on mango in North Gojam, Amhara Region, Ethiopia

2026-10-08T11:25:52Z

Seasonal Population Dynamics of White Mango Scale (Aulacaspis tubercularis (Hemiptera: Diaspididae) on mango in North Gojam, Amhara Region, Ethiopia Yeshiwas, Birhanu In Ethiopia, mango (Mangifera indica L.) is the most widely grown fruit crop. Including the study area, Mango production in Ethiopia is damaged by various insect pests, one of them is the white mango scale, which is the most significant insect pest that causes severe damage to mango tree. It spread and now causes a loss between 50% and 100% to the production of mangoes by affecting the financial gains of mango growers. Therefore, the objective of this study was to examine the population dynamics of the white mango scale, as well as the impact of some basic climatic factors on the population density of the white mango scale in the study areas. The study on the dynamics of Aulacaspis tubercularis was carried out in the north Gojjam administration zone of Ethiopia from December 2022 to November 2023. Bahir Dar zuria and North Mecha district were purposefully selected for the study of this investigation. From each woreda, two representative sites or orchards were selected for the study. From each site/orchard, five mango trees were purposefully selected, and twelve mango leaves were plucked monthly from each mango tree (four at the upper, four at the middle, and four at the lower portion) at each of the four cardinal directions of the tree (female male, egg, crawlers were counted and recorded). Data related to meteorology, including maximum and minimum temperatures, mean temperature, relative humidity, and rainfall, was obtained from the Ethiopian National Meteorological institute and analyzed using R-Statistics software version 4.3.1. The results of the study confirmed that white mango scale was identified in all sampled study areas throughout the study period with a fluctuating population density. The mean number of white mango scale showed significant differences (p< 0.05) among the study months in each location, tree directions and canopy positions. The population density of white mango scale was significantly higher at Dek than in the rest of the study areas (p<0.05). There was a marked increase in white mango population density from March to mid-June with the general trend of slight to moderately increased precipitation. In contrast, there was a swift decrease in the white mango population from mid-June to September, followed by prolonged heavy precipitation. The correlation coefficient between the white mango scale population and some basic weather factors, including maximum temperature, minimum temperature, and relative humidity, showed a weak to very strong positive correlation and a weak positive to weak negative correlation with rain fall in the four study areas. The results of the study showed that white mango scale is distributed in all four cardinal directions, with the white mango scale insect preferring the southern cardinal direction. Furthermore, the study investigated whether the buildup and decline of the white mango scale are affected by basic climatic factors such as temperature and rainfall, relative humidity, and cardinal direction differences, where the other contributing factors need to be investigated further.

Evaluation of aqueous extracts of Botanicals to manage Cabbage Aphid (Brevicoryne brassicae L. (Hemiptera: Aphididae) on Cabbage (Brassicae oleraceae L.) at Koga Irrigation Scheme, North Mecha District, Ethiopia

2026-10-08T11:21:33Z

Evaluation of aqueous extracts of Botanicals to manage Cabbage Aphid (Brevicoryne brassicae L. (Hemiptera: Aphididae) on Cabbage (Brassicae oleraceae L.) at Koga Irrigation Scheme, North Mecha District, Ethiopia Ayenew, Wubayehu Cabbage is one of the most important vegetable crops that grown throughout the world, especially in Africa including Ethiopia. Cabbage aphid is one of the most important a sap sucking insect pest that damage cabbage crops. The aim of this study was to evaluate the efficacy of botanicals aqueous extract against cabbage aphids. The field experiment was carried out at Koga irrigation scheme, North Mecha district, Ethiopia. The experiment was conducted in Randomized Complete Block Design (RCBD) with 14 treatments along with standard check Dimethoate 40% E.C and untreated control with three replications. Four types of botanical extracts such as Nicotiana tabacum L, phytolacca dodecadra, Otostegia integrifolia and Dodonaea angustifolia leave extracts were applied at intervals of one week in the concentration of 2.5%, 5% and 7.5% respectively. But Dodonaea angustifolia leave extracts were applied at intervals of one week in the concentration of 7.5%, 10% and 12.5% respectively. "Copenhagen." Varity was used as a test crop and SAS version 9.4 was used to evaluate the data after it was entered. These research finding shown that all botanical concentrations were completely assuring in terms of their effects on aphid infestation, efficacy on cabbage aphid population, production of cabbage heads, plant canopy spread, plant height, Yield and yield loss. In terms of cabbage aphids, every plant based treatment was harmful. In this study, the Endod leaves (5 and 7.5%) concentration produced the best results among the treatments. Less yield loss was seen in the cabbage crops, a lower infestation level, a greater efficacy level, and a maximum marketable yield that was comparable with standard check. A 68.8% yield loss was recorded in untreated plots. Endod leaves extract with a concentration of 5% and 7.5% are the best for the management of cabbage aphid. Further studies should be conducted on effectiveness of these botanicals in different season.

Management of Tomato Leaf Miner (Tuta absoluta Meyrick) on Tomato (Solanum lycopersicum) Using Botanical and Synthetic Insecticide in Fogera, Northwestern Ethiopia

2026-10-08T11:18:28Z

Management of Tomato Leaf Miner (Tuta absoluta Meyrick) on Tomato (Solanum lycopersicum) Using Botanical and Synthetic Insecticide in Fogera, Northwestern Ethiopia Teshome, Lemat The tomato leaf miner (Tuta absoluta) is an important insect pest affecting Solanaceae plant worldwide. It pose a significant threat to tomato production in Fogera, Northwest Ethiopia. However; study has not yet been made for effective management of this insect by using botanical and synthetic insecticide in these area. Therefore these studies were intended to manage T. absoluta on tomatoes through by using botanical and synthetic insecticide. The study was conducted during 2022 dry season using irrigation in Fogera, Northwest Ethiopia where the tomato variety “Cochoro” was used as a test crop. The experiment consisted of fourteen (14) treatments which are two botanical insecticides, Neem (Azadirachta indica) and Garlic (Allium sativum L.), a synthetic insecticide, Mercury 23 EC 0.14 ml, 0.28 ml and 0.42 ml and an integration of each together through sequential application. The experiment was laid out in Randomized Complete Block Design with three replications. Data on mortality of T. absoluta, infested leaves, tunneled fruit and marketable yield of tomato were collected timely as per their respective standard procedure and analyzed using R-Software version 4.3.1. The results of the study had shown that an integration of botanical with synthetic insecticide influenced most of the tested parameters. Accordingly, the highest mortality of T. absoluta (100%), lowest infested leaves (5.44), lowest tunneled fruit (0.33), highest marketable yield (35.06 ton/ha) and lowest yield loss percentage (<4.10%) were recorded from treatment which consisted of an integration of neem and garlic with Mercury 23 EC 0.28 ml. Similarly this treatments also generated the highest net benefit (350349.94 ETB/ha) with the highest marginal rate of return (553.01%). The yield loss due to T. absoluta was found 81.41%. The current study clearly showed that yield loss positively correlated with infestation of tomato by T. absoluta. Neem and garlic with MERCURY 23 EC 0.28 ml can be recommended as the most effective and economical management of T. absoluta on tomato under irrigation in the study area and areas with similar agro-ecologies.